The invention relates to a piston lock of the type comprising a stator, a rotor pivoting in a bore in the stator and a plurality of stator piston-rotor piston pairings which are urged resiliently towards a key channel provided axially in the said rotor, a coded key sliding in the said passage and comprising slats, each of which co-operates with one of the said pairings in order to displace it against the action of the said resilient means in such a way that the plane of separation between each rotor piston and each stator piston of one pairing is tangent to the said rotor.
Such locks have been known since time immemorial. With the development of mass production techniques which are more or less automated, the known locks have the drawback that the combination determined by the pairs of pistons is imposed generally from the outset of manufacture of a lock which comprises such a locking mechanism so that automatic manufacture is very complicated and expensive. In addition, this problem is complicated when it is necessary to produce a plurality of locking mechanisms having the same combination which form a collection. This is particularly the case in the motor vehicle industry when it is desired that a single key operate with the locking mechanisms of doors and/or the anti-theft device and/or the petrol cap and/or the glove compartment and/or the boot.